...

*** Todo: make equations much nicer

Assumptions: 

Hermes II architecture for both stages

...

O3400 CTI motor – propellant mass estimate for S2 

Summary of calculations: 

SEE APPENDIX BELOW FOR MASS ESTIMATION SPREADSHEETS

...

However, we should still strive to improve the second stage dry mass, as we'll likely increase the mass of the rocket as time goes on, and there may be more drag or cosine losses due to staging than anticipated! 

Recommendations for S2

The following recommendations are given for the second stage to improve its performance:   

...

These are preliminary estimates with plenty of assumptions made, all intended to inform future analysis. 

Semi-known potential changes: 

The following factors may improve the available mass of the second stage:

• Additional propellant mass on the first stage due to monolithic geometry 
• Change in Isp for sustainer motor propellant 
• Better fin analysis and optimization
• Nose cone layup improvements
• Data from main parachute deployment to understand loads on rocket --> decrease structural mass

Appendix – Mass Estimation:

Hermes III Mass estimation: 2/10 Hermes II Mass budget with the following anticipated changes:

...